What are liquidity pools on PancakeSwap ?

The previous weeks I am investing in DeFi projects that are built on the Binance Smart Chain (BSC). I know how to use the tools, I know how to swap, I know hot to connect my MetaMask wallet, I know how to provide liquidity to the liquidity pools, but I also have questions.

What is exactly a liquidity pool?
How does a liquidity pool work?
What is AMM?
How is the price set within a liquidity pool?
What is impermanent loss?